Update dev install doc and single test run (#1223)

* docs: correct npm run e2e

* docs: better use npm ci than install

to fully rely on package-lock.json and not possibly modify it unintentionally

* docs: dev uses node-gyp and requires python and c/c++ compiler tools

* fix(test): missing chai.should init, to run given spec only in the ide

* style: format readme

README.md

@@ -122,12 +122,17 @@ Issues that have to do with the Inspector specifically can be reported here at t
 Want to help us develop this app? We'd love it! Getting set up to do development is pretty easy:
 
 1. Clone the repo
-2. Install dependencies (`npm install`)
+2. Install dependencies (`npm ci`)
+
+> **Note** There are some possible requirements prior to the install, because of [node-gyp](https://github.com/nodejs/node-gyp#installation):
+>
+> - [Python](https://www.python.org/)
+> - some C/C++ compiler tools matching your operating system
 
 From here, have a look at the `scripts` field of our package.json to see what kind of dev scripts you might want to run. Some of the most useful are:
 
 - `npm test`: run basic lint and unit tests
-- `npm e2e`: run E2E tests
+- `npm run e2e`: run E2E tests
 - `npm run dev`: run the app in dev mode (will refresh when you make code changes)
 - `npm run build`: build the production version of the app into `dist/`
 - `npm run build:browser`: build a version of the app for web browsers into `dist-browser/`

test/unit/webview-helpers-specs.js

@@ -5,6 +5,7 @@ import {join} from 'path';
 
 import {parseSource} from '../../app/renderer/lib/webview-helpers';
 
+chai.should();
 chai.use(chaiAsPromised);
 
 describe('webview-helpers.js', function () {